Artificial-tooth structure



Sept. 9, 1924. 1,507,823

I J. A. GARDNER Y Y ARTIFICIAL TOOTH STRUCTURE Filed Feb Fza. J

I [NW/V702 Joseph A. Gardner:

- WHTTORNEY Patented Sept. 9, 1924.

UNITED STATES JOSEPH A; GARDNER, OF MEMPHIS, TENNESSEE.

ARTIFICIAL-TOOTH STRUCTURE.

Application filed February 29, 1924. Serial No. 695,929.

To all whom it may concern:

Be it knownthat I, JOSEPH A. Ganofrna, a citizen of the United States, residing at Memphis, county of Shelby, and State of Tennessee, have invented certain new and useful Improvements in Artificial-Tooth Structures, of which the following is a full, clear, and exact description, such as will enable anyone skilled in the art to make and use the same.

My invention relates to porcelain tooth crowns and interlocking backings or support therefor and especially to that particular class of tooth crowns which are to be built up and either singly or in connection with other crowns or dummies are to be built into a bridge which is to be supported by attachment to adjacent teeth. In this class of dental work porcelain fronts or facings of various sizes and shapes'and of an extensive range of shades of white are used. The exact shade of these facings cannot be determined before burning and it is necemary that they be pre-formed and burned in order that proper selection can be made. These facings are carefully selected to as nearly as possible match the shades of the adjacent I teeth with which they are to be used and are selected of the .proper size and type to properly replace the missing teeth. It is then necessary to' make a bacln'ng on which these fronts ma be roperly aligned and spaced and by w ich t ey may be'attached to and supported by adjacent sound teeth. It is also desirable if this work is to be done in a first class manner to build up the root end of these facings and over the root end of the backing so that a smooth ridge-la. or a smooth and polished root end whic conforms exactly tqthe shape of the cavity in the gum left'by the removal of the tooth, is formed. In doing this work, it becomes necessary -to attach the tooth facing to the backing and detach it from the same a number of times during the progress of the work. First, it is necessaryto attach these together in order that a proper ridge-lap, or a root member may be built-up. It is then necessary to detach the backing in order that this lap or this root member which is preferably of porcelain, may be properly baked to fuse or vitri it to the facing without damage to the acking or without damaging the facin by reason of the unequal expansion of t e bacln'ng and the facing. It is then necessary to attach the backing to the facing in order to properly align and space the facing or facings with reference to the adjacent teeth or to themselves or both and this having been done it is necessary to remove these facings in order that the backing may be properly united into a sin le unit, a process which if carried out, wit the facings attached would result in the cracking of the facings because of the expansion of the backing, and finally when the individual tooth structures have been built and the backing completed, it is necessary to assemble and join each tooth facing at and to its proper place on the backing.

While this outlines the steps necessary in the work, it is ordinarily necessary to attach each facing to, and remove the same from, the backing and to attach each facin and 'root to, and remove the same from, the ackingquite a number of times instead of the limited number mentioned above.

The object of my invention is to make a tooth facing and backing therefor which maybe readily attached to or detached from each other both before and after the root has been built on. I carry out this object as will be more fully hereinafter set out in the drawings, specification and claims.

In the drawings, which are on a scale much larger than the true size; 7

Fig. 1 is areverse view of a tooth facing with the corresponding backing therefor shown detached; one-half of the backing having been cut away to more clearly show the locking member which engages the tooth facing.

. Fig. 2 is a similar view showing two lockin members instead of one.

Fig. 3 is a horizontal section through one oFf the backing plates, on the line III--III of Figs. 6, 7 and 8 are slmilarv views of a ig. is a front view of the backing plate,

plate having a slightly different form of locking member, Fig; 5 showing the plate and locking member engaged with the tooth facing.

Fig. 9 shows a vertical section through a. tooth facing with a portion of the root end of th facing ground away to permit building on the root section and with the backing plate in place. 1

Fig. 10 is a similar section showing the root structure built in place and the back ing member still interlocked.

lg. 11 is a similar section showing the backing section ready to be replaced after the root section has been baked on.

Fig. 12 is a side elevation showing the root section completed and the backing plate again inserted and built up. I

F ig. 13 is a vertical section through a tooth facing showing a locking member without backing plate engaged with the groove in the back of the tooth facing.

Referring now to the drawings in which the various parts are indicated by numerals. 1 is the tooth facing which ordinarily is approximately one-half the thickness of a 00th. 2 is the occlnsal end, and '3 the root end, the front 4 of this facingbeing of the shape of the front of the desired tooth. The back of theifacing 5 is preferably a fiat surface in which is formed a groove 6 having undercut sides, this groove ordinarily opening into the root end 3 but not extending through to the occlusal end 2. At the occlusal end of this groove the sides of the undercut groove 6 are cut away and a straight sided opening 7 formed thereinto. The backin plate 8 is a thin plate ordinarily of go d or platinum which plate has a projecting member 9 adapted to slide in the roove 6 and hold the plate firmly against .t e back 5 of the tooth. This member 9 may be inserted in the open end of the groove 6, or it may be inserted in the groove throu h the enlarged opening 7, and then shifted longitudinally to secure the plate to the tooth facing.

In Fig. 3 the tooth facing is identical in every respect exceptthat it has been provided with two openings 7, 7 into which members 9, 9 projecting from the plate 8 may be inserted. With this form of tooth facing the plate 8 with a single member 9 may be used or the plate 8 with the double members 9 9 asvmay be desired, or even members 9 (Fig. 13) without pro-attached backing plate.

In Figs. 3, 4 and 5 I show the plate 8 gith the members 9*, 9 projecting there- In Fig. 9 I show a section of the tooth facing 1 with the root end 3 thereof ground off to permit building up the root structure thereon. At this stage of the work, the plate 8 may be inserted into the groove 6 from either end; that is, it may be put in at the root end and pulled into the slot or it -may he slipped in through the opening 7 and shifted to place. When however, as shown in Fig. 10, the root structure 3 has been built in place on the root end of the facing 1, the former open end of the slot 6 1n the root end of the tooth facing is closed and it would therefore be impossible to remove the backing plate therefrom were 8 be left in place while this baking is being accomplished, the expansion of the gold would be such as to crack the, porcelain structure of the facing, and in many cases,

the heat necessary to vitrify the porcelain 1 would be suficient to soften and distort or even melt the 'gold backing plate even should the expansion not cause trouble. It will therefor be seen that it is necessary that the plate be removed, and a number of makeshift efforts have previously been made to accomplish this result.

After baking the porcelain, the backin plates can also be easily replaced for the purpose of assembling the teeth and shapingup the bridge ready for completion and after this assembly has been made, the toothfac- .ings may be readily removed to complete the bridge structure,- and thereafter be as readily replaced and finally cemented thereto to complete the assembly.

It is also possible as indicated in Fig. 13, to use a locking member 9 which is not preattached to a backing. In such. case the locking member is placed in proper position in the groove 6 of the tooth facing as shown and a wax backing 10 is shaped thereover. Thereafter the wax backin ing member 9 attached is withdrawn, an investment mold made, and a casting made in the usual manner with the locking member secured to the backing.

It will be especially noted that the shape of the locking member is not material so long as it may be inserted through the opening into the groove and when shifted, engages the sides of the groove to hold the -backing plate against the backing, and the means for securing the locking member to the plate is also not material so long as it be secured firmly thereto.

with the lock- It will also be noted that the groove is not necessarily open at the root end of the facing though shown that way.

Having now fully described my invention, what I claim and desire to secure by Letters Patent of the United States, is

1; A tooth facing approximately one-half tooth thickness, having a groove with under cut sides in the back thereof, said groove being open at the root end of said facing and extending toward, but not to the occlusal edge of said facing, and having a portion of the said sides cut away whereby openings are provided into both ends of said groove.

2. A tooth facing having a groove with undercut sides in the back thereof, said groove being open at the root end of said facing and extending toward but not to the occlusal edge of said facing and having a portion of the said sides cut away whereby openings are provided into both ends of the said oove.

3. tooth facing having a oove with undercut sides in the back t ereof, said groove extending the major portion of the ength of said facing and having portions,

minor in length, of the sides of said groove cut away to provide openings thereinto.

4. A tooth facing having in the back thereof a longitudinal groove with undercut sides extending from a point near the occlusal end of said facing toward the root end-thereof,

v major portion of the length of said facing,

. tion of said groove, whereby said and having a portionof the said sides cut away to provide an opening thereinto of minor length as compared with the length of the remaining portion of the groove.

6. The combination with a tooth facing, having a longitudinal groove with undercut sides 1n the back thereof, said groove extending lon 'tudinally a major portion of the length 0 said facing and having a minor portion of the length of said sides cut away to provide an opening into the said groove of minor length as compared to the remaining length of the undercut groove; of a backing plate therefor provided with a forwardly extending mom or adapted to enter said groove through the opemng thereinto and to be longitudinally shifted to engage with the undercut sides of said groove at any portion of the entire length of the undercut secplate may be shifted to adjust its position ongitudinally with reference to sand tooth facing.

7. The combination with a tooth facing, having a longitudinal groove with undercut. sides in the back thereof, said groove being open at the root end of said facing and extending longitudinally a major portion of the length of said facing and havi i a minor portion of the length of said si es cut away near the oc usal nd of said groove to provide an opening into the said groove of minor length as compared to the remaining length of the undercut groove; of a backing plate therefor pzovided with'a forwardly extending memr adapted to enter said groove through the opening thereinto or the open end thereof and to be longitudinally shifted to engage 4 with the undercut sides of said groove at any portion of the entire length of the under-' cut section of said groove whereby said plate may be shifted toadjust its position longitudinally with reference to said tooth facing, or may be removed from either end thereof.

8. The combination with a tooth facing provided in the back thereof, with a longitudinal groove having undercut sides; said groove being open at the root end of said tooth and extending therefrom to a point near the occlusal end of said facing and having a minor portion of the sides of said groove cut away to provide an opening into the said groove at the occlusal end thereof;

.of a backing plate therefor, providedwith a forwardly extendin member adapted to enter said groove at either end thereof and to be shifted to engage with the undercut sides of said groove and hold said plate against the back of said facing at any portion of the length of the remaining undercut portion of said groove.

-9. The combination with a tooth facing provided in the back thereof with a longitudinal groove having undercut sides extendm from a point intermediate the ends of sald tooth face toward the root end thereof and having portions of the sides of said my name.

JOSEPH A. GARDNER. Witnesses:

F. G. Pearson, Sm From. 

